Good Intenal Filter to Recommend for a 31G/118l Tank?

[faithful]

Hi!

I currently have this tank that has been running for the past year or so. It is planted rather scarcely with a driftwood that acts as a focal point. There is some Crypts that I'm trying to grow to fill in the tank better, but given the size of the specimens I've bought and their growth rate in a low-tech tank, they have remained considerably small. I also have an unknown species of the Echinodorus genus, but that too is on the small side despite having put out several leaves after I've managed to get a bottle of WonderGro Root+. The tank is also being filtered with two powerheads -- one directs flow into a side sump which I fill with medium, another directs flow into the tank itself. Both filters are have a rate of 1000l/hr and more. Yet, I am still having a considerable amount of debri and mulm resting on the sand substrate I have in the tank.

The tank is not stocked with anything yet, other than a couple of cherry shrimp sub-adults and, of course, snails. It seems that the snails I have -- pond snails and MTS -- produce a lot of waste despite the occasional feeding. I do siphon the tank once every fortnight (since there is basically no bioload) to remove the mulm. But after so long, the accumulation of mulm is so severe that the sand substrate looks grey like it has a layer of dust on it and patches of brown debri just lay undisturbed by the "current".

Given the little obtrusion of water flow (small plants and minimal hardscape) and filters which are rated to be able to give a turnover rate of nearly 20x, the presence of so much mulm is worrying me considerably. I am looking forward to stocking my tank with C. pymaeus in these few months which I have come to understand to be the Corydoras season. In light of that, I would want to get filters that are able to better cope with the higher bioload.

Therefore, are there any filters (preferably internal due to the side sump I have) that you guys can recommend? It would be an added bonus if it is cheap (I am a student).

With that said, I have also done a little research on my part and have found apistomaster using a MaxiJet Power Head 600-600lph/160gph in post #95 of this. Another filter I've come across in the Internet is the Hydor Prime 10. Have any of you used these filters before, and was it a good experience?

Below is an old picture of how my tank looks like. Essentially, the Vallisneria nana has been replaced by the Echinodorus as it was dying out on me after sending a few runners that never seem to grow any taller, and the sponge filter removed. The powerhead nearer to the front has also been adjusted lower so that the current produced can pick up some of the mulm, but it doesn't seem to be working. The patch of exposed patch is due to the outflow of the side sump which is really weak -- I use the sump to contain the filter media because the sump will be filled up if the tank is filled to the black border, and breeding mosquitoes isn't in my wishlist. The debri mainly rests near the branch that hugs the substrate, and is usually spread around that area. I apologise for the pathetic photograph but I felt that a picture brings across the idea better than a paragraph of description.

DSC00436.jpg

Thank you for taking the time to read this post. And I look forward to your replies!

- faithful

[stormhawk]

Hello faithful, first off, I might suggest you one of the Fluval U-series filter, perhaps a Fluval U2 or U3. Since it can be placed in a horizontal manner, you can use it to push the debris at the bottom end of the tank, and allow some extra water flow as well. The reason you are seeing the crap on top of the sand is because it is fine, and therefore does not allow the crap to fall through the spaces like with coarse gravel. So invariably, you have to get used to seeing it in a mess most of the time. However, I have not seen these Fluval filters locally except at Pet Safari, and needless to say, the price is on the high side. Checking with shops that stock Fluval products might get you somewhere, but beware, fine sand can damage the impellers in these internal models if they get into the impeller chamber.

I must say, I like your tank though. The simplicity is perfect for C. pygmaeus. If I may suggest, you can totally forget about rooted plants in the sand, and tie some Anubias nana to your driftwood instead, where these little cories love to hang out on. The movements of the Corydoras when they root around for food can easily knock out some rooted plants. Not so much C. pygmaeus, but they are more than capable of digging up some plants by accident during foraging.

[faithful]

Hi stormhawk,

I have heard of Fluval before, and was actually wondering about getting one of the filters from the Fluval Plus series, but the price was way too high for me to even consider. Having searched for reviews of the Fluval U-series filters, it seems rather suitable for providing a strong enough current. However, I'm not really sure with the prices I've seen on online shipping sites. If I may, could you please provide me with an estimate of how much Pet Safari sells them for via PM? There isn't an outlet near the places I frequent. Also, I understand that it is against the forum regulations to post prices of goods, and would not want to get you into trouble.

I must say, I like your tank though. The simplicity is perfect for C. pygmaeus. If I may suggest, you can totally forget about rooted plants in the sand, and tie some Anubias nana to your driftwood instead, where these little cories love to hang out on. The movements of the Corydoras when they root around for food can easily knock out some rooted plants. Not so much C. pygmaeus, but they are more than capable of digging up some plants by accident during foraging.

Firstly, thank you for your kind words. This tank was scaped with the ultimate intention of housing a colony of C. pygmaeus, and I'm glad to have a veteran concur with its design.

Next, I do understand your concern about C. pygmaeus being overzealous when foraging for food especially those on the substrate and accidentally uprooting the rooted plants. To prevent that from happening, I've purposely chosen plants that have a huge root system such as Echinodorus and Cryptocoryne, and am planning to allow them to be secured before introducing any fish. I am, afterall, still searching for C. pygmaeus -- so there isn't much of a hurry.

Actually, I've also read about C. pygmaeus being rather shy in aquariums. I was afraid that a starting school of about 15-20 would be insufficient to calm them down -- I am trying to avoid having fish scuttling about whenever a shadow passes the tank; I don't want to have my precious fish risk injuries due to my negligence. It is thus with that mindset that I've chosen the above-mentioned plant for they were said to provide lots of cover while being hardy. And yet, I've seen neither characteristic come through. And frankly speaking, there are 3 separate pieces of Anubias nana in that mess of Java Fern. They just don't show very well with the dark lighting -- I apologise for that. I had initially wanted to buy the bigger Anubias to provide additional cover but was worried that they would ruin the aesthetics of the tank. So, would it still be better to just remove all the rooted plants? Is the driftwood enough to persuade my C. pygmaeus (should they ever be found) to play about in the open areas?

On a separate note, I've noticed that my Malaysian Trumpet Snails (MTS) have been lying motionless on the substrate surface for the past week or two. And just a couple of days back, I'm seeing my pond snails "eating" the flesh of the MTS. There are significantly more empty MTS shells around now too. What could be harming the MTS? Yet my Red Cherry Shrimp sub-adults are still living. I'm feeling rather nervous about stocking C. pygmaeus.

Thank you for helping, and I'm sorry for the long post.

- faithful

[Apistoinka]

Maybe you can try using gex corner filter which comes with rain bar too... Is less than 20 bucks... Hope this might help you... Well it comes in 2 size as in s size and L size... As for flowrate I'm not sure...

[stormhawk]

Yes the GEX filter is a viable option if you're on a budget. You can place it horizontally if you want and the rainbar attachment is quite useful. However, the sponge in the filter clogs up easily, so if you just need it to add current, just remove the sponges and let it run like a water pump of sorts. Other than that, the flow rate may be a little weak for your purposes.

C. pygmaeus are very lively little fish. You can actually keep them in a loose school with C. habrosus as well. These 2 have very different behaviour. When I previously had pygmaeus, they would be out in the open. Just don't do sudden movements and they will spend most of their time happily rooting for food. If you need C. pygmaeus, I saw quite a number of wild-caught C. pygmaeus from Peru while I was at Green Chapter last week. They're young though, but pretty healthy. They like cool water with some water current and will breed when there's heavy rain.

I'm not sure of the prices of the Fluval U filters but IIRC, the smallest one was close to $50 I think. The U4 was above $100 but that was what I remember. Saw them late last year at the Vivocity outlet so the prices may or may not have changed by now. I've not seen them at any other LFS though but I believe those big LFS like Y618 or C328 might have them. The U1,2,3,4 retails in the UK for £15.39, £22.99, £30.51, £38.89 respectively. That's roughly SGD 30 to 76 before shipping fees etc, so $50 is a rough estimate for the U1. I think it is best to make some phone calls to these LFSes before you go down.

[faithful]

Maybe you can try using gex corner filter which comes with rain bar too... Is less than 20 bucks... Hope this might help you... Well it comes in 2 size as in s size and L size... As for flowrate I'm not sure...

Yes the GEX filter is a viable option if you're on a budget. You can place it horizontally if you want and the rainbar attachment is quite useful. However, the sponge in the filter clogs up easily, so if you just need it to add current, just remove the sponges and let it run like a water pump of sorts. Other than that, the flow rate may be a little weak for your purposes.

It seems like both of you have had good experiences with the GEX Corner Power Filter (the GEX corner filter is a box filter and requires an airpump). I'll be sure to keep a lookout for it, and maybe purchase it if it is reasonably priced and there are no other better alternatives. I'd probably remove the sponge too since there is plenty in my side sump.

If you need C. pygmaeus, I saw quite a number of wild-caught C. pygmaeus from Peru while I was at Green Chapter last week. They're young though, but pretty healthy. They like cool water with some water current and will breed when there's heavy rain.

Oh, thanks for the heads-up! But I'm not very keen to travel all the way to Clementi anytime soon with my busy schedule. I'll probably visit Neo Kim Suey Aquarium first, and hopefully they have healthy stock.

What do you mean by cool water? I don't plan to equip the tank with a chiller/fan. So, would the usual temperature be too warm for them?

Thanks for the help!

- faithful

[stormhawk]

I was referring to a mini powerhead made by GEX called the e-Roka. Comes in several sizes. See the image in the link to see the box and the filter. This was originally designed for small tanks and turtle tanks, but it will suit your purposes, since it comes with the rainbar that should disperse your current evenly.

http://shop.fruitmail.net/img_cmdty/...2547012791.jpg

Basically below 28 degrees Celsius, they will be happy. They thrive best in cool waters around 24 degrees Celsius. Mine spawned after a heavy rainfall.

[himyick]

Hi Faithful,
I like the clean look of your tank, looks like a good home for the corys, but was wondering why your side sump is not functioning as it should. Could it be the arrangement of filter material is not optimum? because a side sump when arranged correctly and properly equipped is more than enough for the intended bio load. Based on your description, a pump is used to pump water into the side sump. Sumps normally work on the principle that water level in the main tank is slightly higher than the overflow lip where water overflow into the filter by gravity, which will take it through the various media and chambers before arriving at the return sump, to be pump back into the main tank. Thus having a pump pumping water into the sump sounds strange to me.

As for the debris, i don't think its too big a problem as the constant foraging by the cory cats will serve to stir up the debris and be picked up by the filter. The important thing to aim for is circulation rather than flow rate. I think IF you were to add 2 more 1000L/H internal filters into the tank, is not going to help much.

I'm not expert in cory, but having "not-too-bright" lighting and not-too-strong water circulation are good guidelines to stick to. And I always aim to avoid installing too many pumps in the tank as pumps emits vibrations constantly 24/7, the higher the flow rate the stronger the vibrations, even though its not audible to us. fishes are more sensitive to vibrations as compared to us. (put your ear on the glass pane, you can hear the vibrations). and plants with big root system, tends to absorb nutrient via their roots, thus cannot survive long term in sand substrate.

These are points hopefully can help to guide you along in your project, not meant to discourage you.
Cheers.

[stormhawk]

I think watching these videos might give you an idea of how Corydoras live in the wild:







So as you can see, they come from a variety of habitats that usually have some sort of sandy bottom with lots of detritus lying about. Understandably, detritus is the plague of many sandy bottomed tanks, but this is not a problem as long as your fish are happy. This is how I keep my habrosus in my 4 ft tank. I laid a new layer of fine sand for them to dig in, on top of my existing GEX soil, and they come out into the open more often these days. Over lighter coloured substrate they tend to exhibit pale colours, and considerably darken when the sand is darker in colour. Plus, I think you can see the sand is not perfectly "clean" but has some poop and bits of other detritus lying about.



As you can see, the colours are light, but when I first got them at GC, they were darker in colour. In brightly light tanks they too will turn a little pale.

Current while not necessary at times, is appreciated by the Corydoras, as they occasionally enjoy "surfing" the current. Not too much though but they will spend a lot of time rooting about. The key is not to create a turbulent flow of water, but a gentle one with the stream of water being broken up by strategically placed rocks and pebbles, much like the eddies in a small stream.

See this video to see what I mean with the rocks and pebbles:



himyick has a point however, in that without some form of root fertilisation, your rooted plants with extensive root systems will not thrive in such a thin layer of sand that has no form of nutrition for them. I think you might have to consider increasing the sand layer or using root tabs for those plants. I used to keep rooted plants in small plastic pots or tupperwares in such sandy tanks with a layer of fertiliser for them within those pots.

[faithful]

I was referring to a mini powerhead made by GEX called the e-Roka. Comes in several sizes. See the image in the link to see the box and the filter. This was originally designed for small tanks and turtle tanks, but it will suit your purposes, since it comes with the rainbar that should disperse your current evenly.

Okay! Just one more question though, can the powerhead work upside-down? I wish to direct the flow to the substrate, but do not want the filter to take up too much floor space by placing it horizontally.

I like the clean look of your tank, looks like a good home for the corys, but was wondering why your side sump is not functioning as it should. Could it be the arrangement of filter material is not optimum? because a side sump when arranged correctly and properly equipped is more than enough for the intended bio load. Based on your description, a pump is used to pump water into the side sump. Sumps normally work on the principle that water level in the main tank is slightly higher than the overflow lip where water overflow into the filter by gravity, which will take it through the various media and chambers before arriving at the return sump, to be pump back into the main tank. Thus having a pump pumping water into the sump sounds strange to me.

Firstly, thank you for your kind words.

Actually, this tank was found thrown away at my void deck. And since I wanted a bigger tank that is shallower as well to allow me to keep Corydoras, I just picked it up and clean it up real good. I had wanted to not use the side sump but it will start to fill up rather slowly when the tank is filled all the way to the black border. So I had to use it. I think the original owner of the tank had customised it wrongly -- the "overflow lip" is on the sump side and the only opening on the other end (other than those that resulted from peeling silicone) is near the bottom. Somehow, he/she wanted to make use of gravity to pull water from the sump into the main tank. Maybe I will take a few pictures today or tomorrow to let you see.

By the way, when I say a side sump, I do not refer to another tank. It is just a compartment of the tank that holds water. And in this case, it holds up to about 9l of water.

As for the debris, i don't think its too big a problem as the constant foraging by the cory cats will serve to stir up the debris and be picked up by the filter. The important thing to aim for is circulation rather than flow rate. I think IF you were to add 2 more 1000L/H internal filters into the tank, is not going to help much.

Understandably, detritus is the plague of many sandy bottomed tanks, but this is not a problem as long as your fish are happy. This is how I keep my habrosus in my 4 ft tank. I laid a new layer of fine sand for them to dig in, on top of my existing GEX soil, and they come out into the open more often these days. Over lighter coloured substrate they tend to exhibit pale colours, and considerably darken when the sand is darker in colour. Plus, I think you can see the sand is not perfectly "clean" but has some poop and bits of other detritus lying about.

Hmm, I think I have not conveyed my worry well enough. I'm concerned about the debris because given the current bioload (a couple of shrimp and many snails), there is just too much debris around. That is, even with removal almost every fortnight. This led to me thinking that either the filters were too weak or the water circulation insufficient, resulting in dead spots. Hence, the request for better filters. The dirt doesn't really bother me -- I just don't want to have fish die on me because of a filter that is incapable to support life. And I think learning that attaching rainbars would be useful in dispersing the current and would allow better circulation was an unexpected return. I also intend to buy the recommended filter to replace my current powerhead if the fish finds the current too strong.

and plants with big root system, tends to absorb nutrient via their roots, thus cannot survive long term in sand substrate.

himyick has a point however, in that without some form of root fertilisation, your rooted plants with extensive root systems will not thrive in such a thin layer of sand that has no form of nutrition for them. I think you might have to consider increasing the sand layer or using root tabs for those plants. I used to keep rooted plants in small plastic pots or tupperwares in such sandy tanks with a layer of fertiliser for them within those pots.

Indeed, I have come to understand that through first-hand experience. I've had quite a number of plants barely growing with leaves indicating nutrient deficiency. Now, I have placed segments of WonderGro Root+ in the substrate, directly under the plants to act as a source of nutrients. So I think the rooted plants should not have a problem at all.

- faithful

[stormhawk]

Hi again faithful,

I'm not sure if that little powerhead will work upside down. So far, I've only seen it mounted horizontally or upright.

As mentioned, debris is normal with a sand substrate. I think you find it unsightly, but I have a simple method for you to keep it clean. Using a siphon tube, just place it a wee bit above the sand bed and you will be able to siphon out the debris easily. No need for a powerhead addition if space is a premium. I tend to use my finger to create some turbulence just above the sand bed so the debris gets into the water column. Easier to siphon them out without sucking out any bits of sand. You can run the water through a fine mesh fish net so that if any sand does get sucked out, you can collect it at the bottom of your bucket where it will settle, and return it back to the tank.

Other alternative is to just use a fine mesh fish net and swish it just above the sand bed. Then you can just "fish" out the debris, which is what I normally do.

Even in a tank with a powerful filter, it does not always manage to suck out the poop the critters make. As long as your water parameters is fine, the debris is tolerable. 2 days after I laid my sand bed, my plecos and my habrosus were pooping all over. Even with my 2026 filtering the tank, the poop still laid in place. I wish the fish would toilet train themselves.

[faithful]

Using a siphon tube, just place it a wee bit above the sand bed and you will be able to siphon out the debris easily.

I do this too! But less regularly since it takes quite some time to reduce the amount of debris by a significant amount.

Other alternative is to just use a fine mesh fish net and swish it just above the sand bed. Then you can just "fish" out the debris, which is what I normally do.

That's a good idea! Maybe I'll do that next time when the debris starts to become an eyesore.

Even in a tank with a powerful filter, it does not always manage to suck out the poop the critters make. As long as your water parameters is fine, the debris is tolerable. 2 days after I laid my sand bed, my plecos and my habrosus were pooping all over. Even with my 2026 filtering the tank, the poop still laid in place. I wish the fish would toilet train themselves.

I think the last statement would be a dream come true for so many fishkeepers!

I agree about some dirt inevitably remaining on the substrate; I'm just shocked by the amount my tank has managed to accumulate despite filters rated to be more than adequate for a tank this size and with a bioload that's negligible.

Having said that, I did a water change just this weekend to siphon the debris, as well as to rearrange the filters. I heeded the advice of himyick and placed the one of the powerheads in the sump to pump the water out into the main tank. And it works! and the ugly bare spot is gone, at last. I feel kinda silly for not having thought of this before. So for now, I'm going to just observe how this change in arrangement would affect the flow in the tank. I'd probably get a rainbar or two to reduce the strength of the current.

On a separate note, the sand substrate in my tank seems to have this coat of dirt that stays unless I unsettle the sand grains a bit. It's definitely not mulm, and while I understand that it'll be nearly impossible to keep the sand white and pristine, the dirt makes the sand substrate greyish-brown.

I've also had blue-green algae coating the sand substrate too so I suppose I'll be able to recognise if the "dirt" is an algae. The dirt doesn't cover the sand surface like blue-green algae does, but instead seems to coat the sand grains individually. My main question is, is this natural? For those who have sand substrate, have you experienced something similar?

I'll try to get a picture within these two days, though I'm not sure whether the colour will turn up well with my camera.

- faithful

[RonWill]

Just a FYI, that blue-green algae is cynobacteria that photosynthetize like plants and algae but isn't one.

[stormhawk]

faithful,

Visit this blog site - aquariumalgae.blogspot.com - and identify the algae that is bothering you. The layer of "slime" that causes the sand to discolor is actually a bacterial film. It can either be good or bad for your fish, depending on what bacteria is living on it. A key note is to watch your Corydoras, if and when you get some. Should you notice any of them losing their barbels, that means the sand is in bad shape.

You can blame the snails for the poopfest. In my fry tubs my ramshorn snails create so much poop, it outnumbers the poop from the fry.

[himyick]

faithful,
can you show a picture of your side sump?

[faithful]

Visit this blog site - aquariumalgae.blogspot.com - and identify the algae that is bothering you. The layer of "slime" that causes the sand to discolor is actually a bacterial film. It can either be good or bad for your fish, depending on what bacteria is living on it. A key note is to watch your Corydoras, if and when you get some. Should you notice any of them losing their barbels, that means the sand is in bad shape.

The "slime" isn't an algae from what I can tell. I do think I have some silk algae in my floating tub of Flame Moss, though.

DSC00639.jpg

As you can distinctly tell, the middle portion is whiter than the portion to the right. I've just churned the sand at the middle portion during the previous water change. Hence, it appears cleaner. The darker portion is nearer to the rooted plants which I avoid digging around so as not to disturb the roots of these plants. I also notice that an even darker band fringes this darker portion. So, does this look too "dirty", or is it dirty but within reason?

faithful,
can you show a picture of your side sump?

Sorry, I'd totally forgotten about my promise to show you pictures of the side sump. These are taken in a rush, so do pardon the quality.

DSC00640.jpg

The first picture shows the intake of water (look near the rocks) and the outflow of water (look to the left of the filter wool) with the new arrangement. Usually the outflow of water would not be observable as the side sump would be filled up to slightly above the black line.

DSC00643.jpg

The second picture shows the movement of water in the side sump where it flows from the right to the left before being returned to the tank. Pardon the messy arrangement of the filter wool, as the egg crates I use to support the filter media is a little on the short side and have fallen during tank maintenance. I'll arrange it properly and probably add in ceramic noodles when I can find something or longer sections of egg crates to replace the current ones.

Lastly, a picture of the tank that was taken today:

DSC00645.jpg

- faithful